[6.02] The Highly Eccentric Binary HD 2909

TODCOR is a new two-dimensional correlation technique to extract the
radial velocities of the two components of double-line spectroscopic
binaries. In this work we apply TODCOR for the first time to a real system
--- the highly eccentric binary HD 2909. TODCOR has derived
successfully the velocities of the two components, even at phases
when the velocity difference between the primary and the secondary was
very small.

We present an orbital solution which shows that HD 2909 is a spectroscopic
binary with a period of 2127 days and an eccentricity of
$0.951 \pm 0.002$.
This value is second only to the highest eccentricity known for a
spectroscopic binary --- $0.9752 \pm 0.0003$, which was recently found by
Duquennoy et al.
(A\&A, 254, L13, 1992) for Gls 586A.
The discovery of the high eccentricity of Gls 586A and HD 2909 raises some
interesting questions with regard to the tidal evolution of such systems.
These questions and the tidal history of HD 2909 are discussed.
We show that the tidal interaction of HD 2909 was not strong
enough to produce throughout the system lifetime any substantial change in
the semimajor axis and the eccentricity of the orbit, nor in the stellar
rotation.